Plaquemines Parish students made slight gains in subject tests in the school year that ended in May, and the district also maintained one of the state's top high school graduation rates, according to data released Friday.

But a lower number of parish high school students scored at a college-ready level in national tests, according to the data from the state Department of Education.

The parish retained large gains in the state's end-of-course tests made over the last five years. An average 75 percent of students who took the tests scored "Good" or "Excellent" in 2013-14, that's 3 percent higher than in tests administered the previous year, the data show.

Plaquemines also retained one of the state's highest graduation rates - the percentage of high school freshmen students who graduated within four years.

A total 83.8 percent of Plaquemines high school students graduating in May 2013 were freshmen in the fall of 2009. That's the same graduation rate than in the four-year period that ended in May 12, the data show. Plaquemines' graduation rate was the 10th highest among the 69 different school districts in the state in the 2012-13 year.

But the parish saw a drop in the number of high school seniors who scored 18 or more on the ACT. The score is the level at which officials deem students to be college-ready and to qualify for TOPS scholarships.

Plaquemines had 21 fewer seniors score 18 or higher on the ACT in the 2012-13 year compared to the previous year. Despite the drop, more Plaquemines students scored 18 or higher than two years ago. The data released Friday didn't include the total number of seniors who took the test each year, impeding an analysis of whether a lower or higher percentage scored at the college-ready level.

ACT scores are important for high schools, as they are part of the overall performance scores the state assign each school annually.

End-of-Course Tests 2013―2014 Comparison of Average Percent of Students Scoring Good or Excellent

Source: Louisiana Department of Education. Notes: "Passing" is the percentage of students who scored in the top three of four categories: Fair, Good and Excellent. "Proficient," a higher bar, is the percentage of students who scored Good and Excellent. Only Proficient scores count toward a school's annual performance score and letter grade.